Influence of roasting pretreatment on high-oleic rapeseed oil quality evaluated by analytical and sensory approaches

Qualitative and quantitative effects on the contents of minor components of cold-pressed high-oleic rapeseed oil (HORO) were evaluated in a function of different roasting temperatures (80, 100, 120 and 140 degrees C). Along with roasting temperature elevation, a significant increase in the content of total tocopherols up to 32% (mainly gamma-T homologue) and a slight increase of total sterols concentration (up to 5%) were observed, whereas no significant changes in the fatty acid composition occurred during seeds thermal pretreatment. Additionally, an increased degree of hydrolysis and lipid oxidation was reported; however, obtained results were within codex limits. The peroxide value of the oil ranged from 1.30 to 2.34 mEq O-2 kg(-1), while the acid value did not exceed 0.46 mg/KOH g. Principal component analysis was capable of differentiating between rapeseed oils acquired from seeds pretreated with different roasting temperatures.